Animal welfare groups will help Puerto Rico housing project residents pursue legal action after animal control workers seized their pets and hurled them to their deaths from a bridge, an activist said Sunday.

Puerto Rico-based Friends of the Animals, which rescues and rehabilitates abandoned pets and farm animals, and several other groups will help the grieving pet owners aggressively pursue claims of animal cruelty and civil rights violations, said the organization's director, Elizabeth Kracht.

Residents in low-income housing in the north coast city of Barceloneta said animal control workers threatened to evict them last week for keeping dogs or cats. Days after they reluctantly handed their pets over, dozens of animals seized were found thrown to their deaths from a tall bridge in a nearby town.

"These people were given permission by the government to go to the homes of these residents and to take away their pets," Kracht said.

Barceloneta Mayor Sol Luis Fontanez has said the municipality ordered the removal of the pets, but he blamed the massacre on a contractor hired to take the dogs and cats to a shelter. He said he would cancel the contract with the company and that city lawyers were weighing a possible lawsuit.

Phone calls to the contractor, Animal Control Solutions, went unanswered Sunday.